diff --git a/sys/cbor/cbor.c b/sys/cbor/cbor.c
index 1665d79bee..bbb7c65e74 100644
--- a/sys/cbor/cbor.c
+++ b/sys/cbor/cbor.c
@@ -95,7 +95,20 @@
 #define NAN (0.0/0.0)
 #endif
 
+
+/* pack to force aligned access on ARMv7 (buggy GCC) */
+#pragma GCC diagnostic error "-Wcast-align"
+typedef struct __attribute__((packed)) {
+    unsigned char u8;
+    union {
+        uint16_t u16;
+        uint32_t u32;
+        uint64_t u64;
+    } u;
+} cast_align_u8_t;
+
 #ifndef CBOR_NO_FLOAT
+
 /**
  * Convert float @p x to network format
  */
@@ -345,15 +358,15 @@ static size_t decode_int(const cbor_stream_t *s, size_t offset, uint64_t *val)
             break;
 
         case 2:
-            *val = HTONS(*((uint16_t *)&in[1]));
+            *val = HTONS(((cast_align_u8_t *)in)->u.u16);
             break;
 
         case 4:
-            *val = HTONL(*((uint32_t *)&in[1]));
+            *val = HTONL(((cast_align_u8_t *)in)->u.u32);
             break;
 
         default:
-            *val = HTONLL(*((uint64_t *)&in[1]));
+            *val = HTONLL(((cast_align_u8_t *)in)->u.u64);
             break;
     }
 
@@ -565,7 +578,7 @@ size_t cbor_deserialize_float(const cbor_stream_t *stream, size_t offset, float
     unsigned char *data = &stream->data[offset];
 
     if (*data == CBOR_FLOAT32) {
-        *val = ntohf(*(uint32_t *)(data + 1));
+        *val = ntohf(((cast_align_u8_t *)data)->u.u32);
         return 5;
     }
 
@@ -594,7 +607,7 @@ size_t cbor_deserialize_double(const cbor_stream_t *stream, size_t offset, doubl
 
     if (*data == CBOR_FLOAT64) {
         CBOR_ENSURE_SIZE_READ(stream, offset + 9);
-        *val = ntohd(*(uint64_t *)(data + 1));
+        *val = ntohd(((cast_align_u8_t *)data)->u.u64);
         return 9;
     }